Semiconductor chips and the like are mounted on lead frames to provide a plurality of electrical connection leads thereto. Lead frames are manufactured in the prior art from a ribbon or strip of metal comprising a multitude of these frames. It becomes desirable to cut this strip at one stage of production, into convenient lengths of exact size. To insure that the lead frame advances incrementally by the correct distance along its length, and stops just at the precise location under a cutting shear, requires complex mechanical systems which either grasp the strip and index it forward in one stroke or roll the strip under high pressure rollers that may deform and stretch the strip. Neither system is as accurate as would be desirable and neither system allows a convenient change in the length of the incremental advance. The present invention is both accurate and easily adjustable.